1. The Field of the Invention
The present invention relates to transmission of eye information and to transmission of eye information from optoelectronic modules in particular.
2. The Relevant Technology
As fiber optic transmission systems are pushed to higher data rates and longer transmission distances, they are often limited by one or another form of optical dispersion where there is a velocity spread in the components of the signal. This velocity spread tends to spread the optical pulses in time, which causes the pulses that make up the 0's and 1's of most transmission systems to spread into one another, leading to an impairment known as inter-symbol interference (ISI). As ISI increases, it will eventually destroy any clear distinction in the level of a 0 or a 1 (also known as closing the optical eye), which is the basis that most simple detection systems use to make an error free decision.
In these and other communication systems, testing for types of use, errors, and signal integrity can be advantageous. Often, problem identification, analysis, and resolution in communications systems involve capturing a portion of the network data traffic for review and analysis.
The use of electronic equalizers, very common in many other fields, such as radio transmission, copper-based high-speed electronic links, and disk drive read circuits, is now finding applications in optical transmission systems, where they can be used in optical receivers to successfully detect signals which are otherwise unusable in simple receivers. One particular approach includes the use of electronic dispersion compensation.
Electronic dispersion compensation (EDC) attempts to correct for the data waveshape distortions and resultant bit errors caused by the multiple paths and varying arrival times of each path in a fiber. EDC systems are implemented in the receiver with time-domain equalizers having multiple taps and some sort of a automated tuning algorithm that finds a combination of tap gains that improves the received signal by creating a distortion that is opposite and equal and, therefore, cancels the distortion caused by the transmission medium. This is a difficult task and while it helps a lot in some cases, it is quite imperfect and is performed “after the fact.”
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced